1,721,045 research outputs found
Temperature affects Vibrio cholerae O1 El Tor persistence in the aquatic environment via an enhanced expression of GbpA and MSHA adhesins
No full textVibrio cholerae O1 El Tor attachment to chitin and biofilm formation on polyvinylchloride surfaces via the N-acetylglucosamine-binding protein A (GbpA) and the mannose-sensitive haemagglutinin (MSHA) were investigated under different temperature and salinity conditions simulating those found in the aquatic environment. In vitro tests showed that mshA and gbpA defective V. cholerae N16961 strains displayed a significant reduction (P < 0.05) in attachment to chitin in comparison with the parent in all the environmental conditions tested. The lack of mshA, but not gbpA, resulted in a significant decrease (P < 0.05) of V. cholerae N16961 strain ability to form biofilm. Wild-type attachment to chitin and biofilm formation increased from 15°C to 25°C as did gbpA and mshA expression. In situ data obtained analysing zooplankton and water samples collected in coastal waters of NW Mediterranean Sea over an annual cycle showed that the percentage of plankton-associated V. cholerae was positive correlated with sea surface temperature, and increased dramatically at temperature values above 22°C. It is suggested that temperature plays a major role in affecting persistence of V. cholerae in the aquatic environment by promoting colonization of environmental surfaces, via an enhanced expression of both mshA and gbpA
A preliminary study on toothpaste efficacy in reducing levels of S. mutans in dental plaque.
No full textFunctional foods and strategies contrasting bacterial adhesion
No full textAntibacterial strategies targeting bacterial adhesion to substrates are considered a valuable alternative to traditional antibiotic therapy, in view of the great advantage they bring in combating the infectious process at the very early stage without selecting for drug resistant cells. Amongst bioactive compounds with activity against bacterial adhesion, several are found in natural food and beverages, such as cranberry, tea, coffee, wine and milk. For the analysis of their anti-infective potential, successful experimental models can be conducted using different substrates from the oral cavity. Studies conducted so far in this field allowed the discovery of a variety of anti-adhesive fractions and compounds proven to be effective against bacterial traits involved in the development of oral pathologies such as caries and gingivitis/periodontitis. Discovering new anti-adhesive compounds from natural products, unravelling and testing their prophylactic and therapeutic values, and improving their use in the general population are promising new frontiers in the global fight against human infectious diseases
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
The environment as a reservoir for non-culturable but infectious, antibiotic-resistant bacteria: a new risk for human health?
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